And by "hot loads" the Autralian gentleman is referring to primers falling out of the primer pockets when safe pressures have been exceeded. Several of those cartridge cases ARE missing the primers- they may have been deprimed.

Believe the "Big 'un" is the metric designation for a .50 Browning Machine Gun cartridge.

These include- besides rimfire and centerfire, other earler priming systems- pinfires, lipfires, cupfires, teatfires. The two on the white postage stamp sized background are 2 mm cartridges- one rimfire, one pinfire.